Air valve



v March 10, 1 94 2. c. W.-MQUA|D 2,275,786

AIR VALVE Filed Dec. 11, 1939 Patented Mar. 10, 1942 uNi'rEo s'mrEs PATENT OFFICE AIR VALVE Charles W. McQuaid, Des Moines, Iowa Application December 11, 1939, Serial No. 308,682

6 Claims.

My invention has reference to that class of devices used with a fan or blower for modifying a gravity type hot air heating system to give forced circulation.

The invention here described constitutes a modification of and improvement on the device shown in my Patent No. 2,177,220, dated October 24, 1939.

An object of my invention is to provide a structure which makes for eflicient forced circulation when the fan or blower is in operation, and which automatically provides a bypass whereby gravity operation of the heating system is substantially unimpeded when the blower is not running.

Another object is to provide a valve and bypass structure which can be made up as a unit, conveniently insertable into the cold air return duct in a gravity system through an opening in the side of the duct. With such a structure, conversion of a gravity system to a forced circulation system can be made with a minimum of expensive modification of the existing installation.

A further object is to provide a unit structure of the kind described, in which the valve can be adjusted for proper operation under different conditions of installation, particularly the conditions met when the return air duct is at an angle from the vertical, and when the valve must be mounted on the top side of such a sloping duct.

Another object is to provide such a structure which is extremely simple and economical to build and has few moving parts.

With these and other objects in view, my invention consists in the construction, arrangement and combination of the various parts of my device, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims, and illustrated in the accompanying drawing, in which:

Figure 1 is an elevational view showing the relation of the parts of my device to an ordinary hot air furnace and heating system.

Figure 2 is a plan view of the same.

Figure 3 is an enlarged horizontal sectional view on the line 3-3 of Figure 1.

Figure 4 is an enlarged vertical sectional view on the line 4--4 of Figure 2; and

Figure 5 is a View similar to Figure 4 and illustrates the operation of my device when installed in a sloping return air duct.

In the accompanying drawing I have used the reference numeral 10 to indicate generally a hot ing hot air to the various rooms of the house. In the form here shown, it has a return air duct I4, which discharges into the jacket [6 of the furnace I0. I provide a base member l8, preferably supported on springs 20, and carrying a motor 22 which operates a centrifugal blower 24. A propeller type fan or other suitable air moving device can be employed in place of the centrifugal blower 24. The intake to the blower 24 is through the connecting pipe 26 and the chamber 28, which may if desired contain air filters of any suitable kind. The outlet of the blower is through the connecting pipe 30.

In the return air duct I4, I mount a casing referred to generally as 32. Its outer end consists of a wall 34 in which an opening 36 is formed to receive the connecting pipe 26 and an opening 38 is formed to receive the connecting pipe 30. The top wall 40 and the bottom wall 42 are not complete, but extend only from the rear wall 34 to a point slightly within the duct l4. Side walls 44 and 46 of the casing 32 extend well into the duct I4, preferably quite close to the opposite wall of the duct, as may be seen in the sectional View of Figure 3. The side walls 44 and 46 support an end wall which is formed With an upwardly flared portion 48 and a downwardly flared portion 50. An intermediate partition member 52 is located between the top and bottom walls 40 and 42 and substantially parallel thereto. Like the walls 40 and 42, the partition 52 extends only from the rear wall 34 to a point just within the wall of the duct l4. Pivoted at 54 on a substantially horizontal axis, and in close relation to the partition 52, I provide a damper or valve plate indicated generally as 56. I preferably form this plate in such a manner that a greater part of its mass is located below the pivot 54. When this is done, and when the easing 32 is mounted in a vertical duct l4, as shown in Figure 4 of the drawing, the valve 56 hangs normally in the position shown in full lines in Figure 4. By abutment against the down turned flange 58 of the upper wall 40, and the edge 60 of the lower wall 42, the valve 56 thus shuts off the fan inlet connection 26 and the outlet connection 30.

When the blower 24 is in operation, however, a difference of pressure will be created between the connection 26 and the connection 30, which will cause the valve plate 56 to swing on its axis 54 and to assume the position shown in dotted lines in Figure 4. This action takes place because of the suction created by the blower in air furnace which has the pipes I2 for conductthe intake pipe 26 and the blast pressure in the outlet pipe 3%. The resulting currents of air are represented by the dotted arrows in Figure 4. It will be noted that when the valve 56 assumes the dotted line position, its lower end engages the constriction represented by the juncture of portions 48 and 50 of the inner end wall of the casing 32. Direct passage of air through the duct M in the direction represented by the full line arrows in Figure 4 is thus substantially cut off, with resulting high efificiency in the booster action of the blower. The blower may be controlled by a room thermostat or by any other suitable means, and when blower operation ceases, the valve 56 returns to the full line position, and leaves the duct l4 substantially unimpeded so that normal gravity flow in the heat? ing system can continue.

In the practical installation of devices of this type serious problems arise from the fact that the ideal situation represented in Figure 4, which shows the duct H3 in vertical position, is seldom met. As is Well known, the duct work of hot air :heating systems is installed in whatever manner is most convenient and economical for the installer. Consequently, the cold air return ducts are found at many different angles of inclination. Access to them is often difficult or restricted by adjoining walls or by fixtures of various kinds. Consequently it is sometimes necessary, in making the modifications for a forced circulation installation, to install my valve and bypass casing 32 on the upper side of an inclined duct represented as l lo in Figure 5. In this case it will be noted that when the fan is not operating, the valve plate 55, if it stood in a substantially vertical position, would leave the connections 26 and 3t partly opened and would also partly shut olT the normal gravity flow through the duct Ma. This diificulty I have overcome by providing a supplementary weight 62, which if desired may be slidably mounted on a rod hinged or pivoted at B6 to the valve plate at some point thereon above the pivot 54. In Figures 4 and 5, it will be noted that in the dotted line position of the valve 56, its normal tendency is to rotate toward a vertical position, both because of the fact that the greater portion of the plate is below the pivot 54, and also because the weight 62 lies upon the lower portion of the valve. In a case such as that represented in Figure 5 however, it will be seen that as soon as the plate 56 swings through a vertical line, the weight 62, being pivoted freely at 66, will no longer bear against the lower portion of the valve 56, but will swing free thereof. The entire pull of the weight 62 and the rod M will then be exerted through the pivot 66 on the upper half of the valve 56 and will tend to bring it into the full line position of Figure 5. I am thus able to obtain the advantages of the simple and trouble-free operation of a gravity actuated valve, even in installations where it would appear at first glance that a gravity type valve could not function satisfactorily because of the angle at which the device must be mounted.

By providing the control valve and bypass mechanism in a unit such as the casing 32, I make possible a very simple, convenient and inexpensive installation of forced circulation equipment in existing gravity type hot air heating systems. No changes, modifications or rearrangement of existing systems are necessary other than the cutting of an opening in the side of a cold air return duct to receive the valve and bypass unit. The blower and motor, together with the filter cabinet, if one is desired, must be mounted near by, but no connection to the duct work or furnace casing of the old system is necessary, other than that provided through my valve and bypass unit. Where there is more than one return air duct in a particular hot air heating system, a unit such as my casing 32 can be mounted in each such duct, and the connections 26 and 30 may be made plural.

Some changes may be made in the construction and arrangement of the parts of my device without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims, any modified forms of structure or use of mechanical equivalents, which may be reasonably included within their scope.

I claim as my invention:

1. In a damper valve, a valve plate, a pivot mounting for said plate, a member hingedly connected with the portion of said plate which normally lies above the axis of said pivot, and a weight on said member at a distance from the point of said hinged connection greater than the distance from said point of hinged connection to said axis, whereby when said plate is rotated one way from a vertical plane through the axis of the pivot, said weight rests upon the portion of said plate below said axis, and when said plate is rotated the other way from said plane, said member and said weight depend freely from said hinged connection.

2. Flow control means adaptable for insertion in an air duct, comprising a casing, a passage therethrough from top to bottom thereof, an outlet port in the side of said casing, an inlet port below said outlet port, a damper mounted on a pivot between said ports, and a weight attached to the portion of said damper which closes the upper port, whereby said damper is actuated by gravity to stand normally in position closing both said ports, said outlet port and the upper portion of said damper being of a shape permitting said upper portion to rotate about said pivot mounting and move into said outlet port upon the occurrence of low pressure in said port, said passage and the lower portion of said damper being of a shape whereby closure of said passage is simultaneously effected by said lower portion.

3. Means for controlling the circulation through an air duct consisting of a casing adapted to be inserted in the duct, a passage through said casing in the normal direction of air movement in the duct, inlet and outlet ports opening into said casing, a valve pivoted between said ports, a member flexibly connected with the portion of said valve which normally lies above the axis of said pivot, and a weight on said member at a distance from the point of said connection greater than the distance from the point of said connection to said axis, whereby when said valve is rotated one way from a vertical plane through the axis of the pivot, said weight rests on the portion of the valve below the axis, and when the valve is rotated the other way from said plane, said member and said weight depend freely from the flexible connection.

4. Circulation control means including a casing adapted to be inserted in an air duct, a passage through said casing in the normal direction of air movement in the duct, an outlet port connecting with said passage, an inlet port connecting with said passage'below said outlet port, a valve plate mounted-on a pivot between said ports and adapted to cover both ports, and a weight extending from the side of said plate 0pposite said ports, said weight effecting yieldable closure of said valve when said casing is mounted in an inclined position such that with the valve closed the side to which the weight is attached is the underside.

5. Circulation control means including a casing adapted to be inserted in an air duct, a port opening into said casing and adapted to connect with a blower intake, a second port opening into said casing below said first port adapted to connect with a blower outlet, a valve pivotally mounted on an axis lying between said ports, said valve being adapted to hang in a position closing both said ports when subject to the influence of gravity only, and being adapted to be swung to position opening both of said ports by the occurrence of a difierence of pressure between said ports, and a weight hinged to the portion of said valve which normaly closes said first port, said weight normally depending below the pivot axis of said valve.

6. Circulation control means including a casing adapted to be inserted in an air duct, an intake port adapted to connect with said duct, an outlet port adapted to connect with said duct above said intake port, a valve plate pivotally mounted between said ports, and a weight pivotally attached to the upper portion of said valve plate, said plate being adapted thereby to hang, when subject to gravity only, in a position effecting closure of both said ports, and being adapted to move, when subject to difierence of pressure betwen said ports, to a position opening both said ports, the portion of said plate below said pivot being shaped to close off a substantial portion of the cross-section of said duct when in said second-mentioned position.

CHARLES W. MCQUAID. 

